Chain driven vehicles



United States Patent [72] Inventors Bernard Hooper Stourbridge;

[56] References Cited UNITED STATES PATENTS Robert Victor Trigg,Birmingham, England Attorney-Kurt Kelman ABSTRACT: The disclosuredescribes motor th cycles in which e rear road wheel is mounted in afork swinging on the 'menta Nav". 24, 1970 Sheet 2g of 7 Patented Nov.24, 1970 3,542,146

Sheet L of 7 x '.IYIIIIIIYGQ, VIII 64 uw' MMM Patented Nov. 24, 1970Sheet 7 of 7 l (uve/wrom.' fBe@ NAR Above? @www vmwrmm@ 1 CHAINyDR'IVIIN VEHICLES".

BACKGROUND OF TI-IE` INVENTION l. Field ofth'e'lnvention" i Theinventionis concernedwith chain-driven vehicles and 5 particularlymotorc'ylces i.e. all fsteerablerf'" twowheeled, power-driven vehicles.

2. Description of the PriorArt.

It has been proposed to mount the engine of a motorcycle l resilientlyin the'frame thereofwitha view to reducingthe vibrations transmittedfromfthe 'engine to the frarneqlt has beenfound, however, thatwithsuchresilient mounting,r-when the engine is under load'it tends toi`twistabout-a verticalaxis due to the chainpull. As a result,lthedistance between th'een'- gine and thedriven wheel tends to shortenwith va danger that the driving chain may become disengaged.-` Moreover,the en? gine mounting has to withstand the `whleof the chain' tensionand hasto be strong enough' "to avoidvcollapse-butnot so stiff as togive little aitmiat of engine Viban"'Thispmblem 20'ia second kind -andmounts the engine resiliently for said movehasto some extent beenvsolved byiitting between the engine and the frame oneor more linkswhich allow'the'enginesome" movement in a `vertical plane'butrestrain'the 'engine from Y twisting about a vertical'axis,thelflinkstendingjto restrain movement of the engine rearwardly which"wouldshorten' the z 25 distance between the engine andthe drivenjwheel. However,- even in this constructionthere is considerablevibration 'transr mitted from the engine to the frame throughthe-links.l

It is normal motorcycle `practice 'at'fpresent' to Vmount the rear,driven wheel in a swinging fork which ispivoted at itsifor- 30 ward endto the frame, carries thefwheel between itsv rearwardly-extending limbs"and isV connected to 'the rear spring dampers which arealso connected tothe frame;

SUMMARY 0F THE INVENTION axis of rotation of said road wheeL'thepermitted amplitude-of 45 such movement in said first directionsfrom aneutral position of the power unitin the frame being? greater than-.theper-` mitted amplitude of3x such movement in saidA second directions. l

Thus thepermitted relativemovement` is greater in planes 50` parallel tothe 'planeof the driving wheeland lessereinplanesf perpendicular to theplane ofsaid wheel, theJplane-ofsuchl wheel being theplanethroughth'ecenter of thefwheel andperpendicular to the rotary axisthereof.

By virtue of the foregoingv construction, the-engine `isal- 55` loweddisplacements whilel resilientlyfmounted in said first directions sothat vibrations passed onto the frameare'largely attenuated. Since-theswinging fork isfpivoted tothe power unit rather than to the'fram'e, thedistance betweenthe power unit and the driven wheel cannot alterunde'rloadsothat there 60 is no danger` of theL chain drive becomingdisengaged. Moreover, any tendency of the power unit topivotfabouta.

'vertical axis relative to the wheel willbe.restrained by the` pivotalconnection betweenthe fork and thefp'ower unit.

Preferably, the resilient mounting meansy comprise three165`spaced-apart, resilientmountings between `the power unitand the frameand located at'the apices of a triangle lying inthe plane of thedrivingwheel. Preferably, at least'o'ne of said mountings is of a firstl kindandmounts the engine resilientlyfor said movement in said firstdirections and provides 70 clearancefor said movement insaidseconddirections: The (or each) mounting of said'first kind may.comprise a'shaft secured to the frame or the power unit, a tubularassembly sur' rounding the shaft andsecured to th'e power unit or theframe,

. and resilient bushes' interposed betweenthe-tubular assembly 75 andthe shaft andfarranged so that said clearance allows the I A whichengages the shaft and to an outer metal sleeve which engagesga mountingsleeve tixed'toth'e power unit or the frame, the outerandmountingsleeves forming the tubular assembly. Alternatively, eachresilient bush may be bonded to an inner `metal sleeve only whichengages'the shaft and the bush may engage directly a mountingsleevefixed to the power unit or frame and forming the tubular assembly.

In thev foregoing constructions, there mayV be further resilientbushes^mounted on the shaft and of lesser cross-sec- 5 tional size thanthe first mentioned bushes so that there is ments in both said first andsecond directions, the compliance of said'mountingbeing greater in saidfirst directions than in said second directions. `In other words, thedeflection of the mounting `for a given force is greater in said firstdirections than in said second directions.

The (or each) mounting of the second kind may comprise one'or moreresilient discs, the (or each) disc being arranged so thatit is incompression'in a direction perpendicular to its 'faces; saiddirectionbeingparallel `to said second directions,

and has its opposite faces connected to the frame and power unit'respectively so that the disc is in shear parallelto:said facesduringsaid movement in said second directions-'By corn- Vpressing the disc inthe direction perpendicular to its faces the shear properties thereofare improved.`

Two of the three resilient mountings may be of the tirst kind beingarranged betweenthe lower part of the power unit and thefr'ame, thethird resilient mounting being of the second kind "and being mounted in`between anl upper part of the .power unit and the frame.

Thepower unit may l.solely be an engine if no gearbox is provided or'maybe a unitary engine andv gearbox. In another arrangement, the .powerunit may comprise a separateengine and gearbox, thelatter being chaindriven from the engine and the .engine and gearbox vbeing interconnectedby mounting plates.

BRIEF 'DESCRIPTION OF THE DRAWING FIGV.-5is a horizontal section throughthe pivot mounting of athe swinging rear fork ofthe motorcycle of FIG.1;

FIG. 6-isa detailed sectionof a modification applicable to themountingsof'FIGS'. 2 and 3;

FIG. 7 is a perspective view of a motorcycle constituting a furtherembodiment of the invention and using a unitary engine and gearbox;

FIGS`;' Sand 9 are horizontal sections through the lower front and rearengine mountings to the motorcycle of FIG. 7;4

FIG. 10'is a horizontal sectionl through the pivot mounting ofthe rearswinging fork of the motorcycle of FIG. 7;

FIG. ll'is` a detailed section of a modification applicable to themountings of FIGS. 8'and 9; and

FIG. 12 isV a detail section applicable to the mountings of FIGS 2, Sand8',y 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIGS. 1 to 5inclusive,the motorcycle thereshown comprises a frame indicatedgenerally at 1 and which is fully described and is claimed inapplication Ser. No. 734,312 now U.S. Pat. No. 3,508,765, filed June 4,1968, by Bernard Hooper, Robert Victor Trigg and Stefan George Bauer, towhich reference should be had. Briefly, the frame comprises a backbone11 which at its forward end supports front forks 12 which in turnsupport a front road wheel 13. Mounted on the frame is an engine 14which is connected to a gearbox 15 by a pair of mounting plates 16.Pivoted to the mounting plates 16 is a rear swinging fork 17 whichcarries the rear road or driving wheel 18. The wheel 18 is driven fromthe gearbox by a chain 19. The swinging fork is connected to suspensionmeans 20 which in turn are connected to the frame 10.

The frame 10 carries lower front engine mounting plates 21 and lowerrear mounting plates 22. The power unit comprising the engine 14, thegear box 15 and the mounting plates 16 is mounted on the frame by afirst resilient mounting 23 interposed between the lower front enginemounting plates 21 and the power unit, by a second resilient mounting 24interposed between the power unit and the rear engine mounting platesand a third resilient mounting 25 interposed between the upper partofthe engine and the backbone 11.

Referring now to FIG. 2, this shows the first resilient mounting and itis interposed between the lower front engine mounting plates 21 andmounting plates 26 secured to the engine 14, the plates 26 beingapertured and carrying a mounting sleeve 27 which is welded to theplates at 28. The lower front engine mounting plates 21 carry a shaft 29which at its ends is provided with lock nuts 30 and washers 3l. Engagingthe shaft 29 are two resilient bushes of similar construction eachindicated generally at-32 and each comprising an inner sleeve 33, arubber annulus 34 and an outer sleeve 35, the annulus being bonded tothe inner and outer sleeves 33 and 35 which are of metal. The innersleeve 33 is a close fit on the shaft 29 and the outer sleeve 35 is aclose fit in the mounting sleeve 27. The sleeves 33 are spaced by meansof a spacer sleeve 36 and the sleeves 35 are spaced by a spacer sleeve37. The spacer sleeve 36 carries two rubber annuli 38 which are oflesser diameter than the annuli 34 and which serve to limit deflectionof the engine relative to the frame as will hereinafter be described.

At its ends, the mounting sleeve 27 carries inner thrust plates 39 whichare formed with flanges 40 which overlie the ends of the mounting sleeve27. The shaft also carries outer thrust plates 41 and between each pairof inner and outer thrust plates which constitute cooperating abutments,there is a polyurethane bearing or antifriction washer 42. Shims 43 areinterposed between each end of the mounting sleeve 27 and the adjacentinner thrust plate 39. A gaiter 44 of flexible material is arranged ateach end of the mounting and each gaiter 44 engages at its one end withthe flange 40 and at its other end with a lower front engine mountingplate 21. The shims 43 are adjusted to give an end float of the shaft 29relative to the mounting sleeve 27 which is between .005 inch and .010inch.

The rear resilient mounting 24 is similar, except in length, to themounting 23. Thus the mounting plates 16 carry a mounting sleeve 44which is welded to the plates 16 at 45 and a shaft 46 is secured to therear mounting plates 22, the shaft carrying lock nuts and washers 47 and48 at its ends.

The shaft 46 carries resilient bushes 49 which are similar inconstruction to the bushes 32, the bushes 49 being spaced by spacersleeves 50 and 5l. The sleeve 51 carries resilient bushes 52 similar tothe bushes 38. The shaft 46 carries at its ends outer thrust plates 53,bearing or antifriction washers 54 and inner thrust plates 55 similar tothe corresponding members 4l, 42 and 39 in FIG. 2, the thrust plates 53and 55 forming cooperating abutments. Shims 56 are placed between theinner thrust plates 55 and the ends of the mounting sleeve 44. As inFIG. 2, the shims 56 are adjusted so that the maximum end float of theshaft 46 relative to the mounting sleeve 44 is approximately 0.010 inch.

Referring now to FIG. 4, this shows the third resilient mounting 25.This mounting extends between a mounting bracket 57 secured to thecylinder head of the engine and two mounting plates 58 welded to thebackbone 11 of the frame. Secured to the mounting bracket 57 by twobolts 59 are a pair of spaced generally triangular plates 60 clearlyshown in FIG. l, the plates 60 each having a peripheral flange 6l togive the plate rigidity. Between each plate 58 and its adjacent plate 60is a resilient mounting bobbin 62 which comprises a pair of metal discs63, each of which has a stud 64 welded thereto, the studs being engagedwith the plates 58 and 63 respectively and held in position by nuts 65.Bonded to the faces ofthe discs 63 is a resilient disc of rubber or likematerial 66 and this is arranged to be in compression in directionsperpendicular to its faces, i.e. in directions indicated by the arrows Xand X.

The operation of the suspension of the power unit is as follows.Considering first the axis of the driven road wheel 18, which axis isindicated 67 in FIG. l, the shafts 29 and 46 ofthe first and secondresilient mountings 23 and 24 respectively are parallel to this ax-isand the directions X X in FIG. 4 are also parallel to this axis. It willbe seen that the mountings 23, 24 and 25 are arranged at the apices of atriangle lying in a plane perpendicular to the axis 67. Movement of thepower unit in all first directions radial to this axis 67 are controlledby the resilient bushes 32 and 49 in the first and second resilientmountings 23 and 24 being loaded in impression and by the resilientdiscs 66 in the third resilient mounting 25 being loaded in shear. Thestatic deflection of the power unit from a neutral position, .e. aposition in which the shafts 29 and 46 are concentric with the mountingsleeves 27 and 44 may be of the order of 0.04 inch. The power unit willvibrate about this static deflected position and components ofvibrations which are in directions radial to the axis 67 will beattenuated by the resilience of the bushes 32 and 49. Duringacceleration of the machine, a load is placed on the engine and thedeflection may reach 0.1 inch and this deflection is limited byengagement of the resilient bushes 38 and 52 with the spacer sleeves 37and 50 in the mountings 23 and 24.

Movement of the power unit in all directions parallel to the axis 67 isresisted by the bushes 32 and 49 being loaded in shear and the amplitudeof such movement is limited by the end float which is left between theshafts 29 and 46 and their associated mounting sleeves 27 and 44 asdescribed above. This end float is considerably less than the amplitudeof deflection allowed in directions radial of the axis 67. Thus by wayof example the maximum end float may be of the order of 0.01 inch asdescribed above but the maximum deflection of the power unit from aneutral position in directions radial of the axis may be 0.1 inch.

Turning now to the operation of the third resilient mounting 25, thecompression of the disc 66 and the arrangement of the bobbins 62 is suchthat the mounting has a greater compliance in direction perpendicular tothe directions X X in FIG. 4, i.e. in directions radial of the axis 67than it does in the directions X X, i.e. directions parallel to the axis67. The discs are thus loaded in shear by movement of the power unit inall directions radial to the axis 67 and are loaded in compression byall such movements parallel to the axis.

The swinging fork 17 is mounted on the plates 16 in the manner shown inFIG. 5. The plates 16 have a sleeve 68 welded between them, the sleevereceiving a shaft 69 which is held in position by a set pin 1). The endsof the shaft are received in flanged bushes 'l which are received in theends 72 of the limbs of the fork, the bushes being shielded by endplates 74 which are clamped together by a pin 75. A protective washer 76protects the flange of each bush 7l. The shaft 69 is provided with oilholes 176 so that the bearings between the shaft and the bushes 71 canbe oiled by removing one of the end plates 74 and introducing oil intothe bore of the shaft 69 which is hollow.

It .will be noted thatthe swinging fork is pivoted -to the power unitcomprising-the engine 14, the gearbox and the mounting plates 16 sothat'there is no possibility of the distance between the rear` roadwheel 18 and the gearbox Vchanging during acceleration and deceleration.We have in its train disadvantages in the drive tothe rear wheel 18 orallowing rear wheel steeringto occur `under load.

Figure 6 shows a modification which is applicable to the mountings 2k3and 24 in that instead of using resilient bushings such as 32 and 49yhaving metal sleeves 35 bonded to the rubber annuli, a resilient brushr77 is bonded to an inner metal sleeve 78 but frictionally 'engagesdirectly a mounting sleeve 79 similar to the mounting sleeve 27 or 44.The frictional engagement is sufficient for the bush to be loadedincshear` by relative movements ofthe power unit and frame parallel tothe axis 67. Otherwise the construction of the mountings is the same asdescribed in relation to FIGS. 2 and 3.

Referring now to FIGS. 7 to 10, this shows an arrangement which isbasically similar to that described with relation to FIGS. 1- to 6except thatthe power unit comprises a unitary engine and gearbox and.thus the lower mountingsare made to the engine casing rather than toplates and the swinging fork is also pivoted to the engine casing.

Referring first to FIG. 7, the motor cycle frame is indicated generallyat 80 and has a backbone 81 which carries forks 82 which in` turn carrya front road wheel 83. Mounted in the frame is .a`power unit indicatedgenerally at 84 which comprises a unitary engineV and gearbox. The powerunit has a casing 85 and is mounted in'the frame by a resilient mounting86 interposed between the casing 85 and lower front engine mountingplates 87," asecond resilient mounting 88 interposed between the casing85 and rear mounting plates 89 and a third resilient mounting 90interposed between the cylinder head of the engine and the backbone 81.4'

lfe first and second mountings 86 and 88 will be described in relationto FIGS. 8 and 9 but the third resilient mounting 90 is exactly asshow'nin FIG. 4 and will not be described further.

Referring to first to FIG. 8, the casing 85 of the engine is providedwith a bore 91 which provides a mounting sleeve for the resilientmounting. Within the bore 91 is mounted a shaft 92 which is connected atits ends to the plates87. The casing 85 is provided, at the endsof thebore 91, with faces 93 which are engaged by shims 95 and the latter byouter thrust plates 96. Flexible gaiters 97 extends between the outerthrust plates and spigots 9 8`and on the casing 85. The shims 95areadjusted to provide the desired end float between the shaft 9 2 and thecasing 85, such end float not exceeding 0.01 inchv normally.

Mounted on thesh'aft 92 are two resilient bushes 99 of the same generalconstruction as the bushes 32of FIG. 2, the bushes 99 being spaced byspacing sleeves 1 00 and 101 and the spacing sleeve 101 carryingresilient bushes 102 of construction similar to the bushes 3 8.

FIG. 9 shown the secondresilient mounting `88 and it will l not bedescribed in detail because it is virtually identical with the mounting86 except that the bore 102 in lthel casing 851s longer than the bore`91 and the `shaft 103 is appropriately longer than the shaft 92. Theresilient mounting comprises bushes 104a similar to thebushes 99 andfurther bushes 104 to limit deflection of the powerunit in a mannerdescribed in relation to FIGS. 2 and 3.

The power unit casing 85 carries aswinging fork indicated generallyv at105 which carriesy the rear road wheel 10511 and the pivotal mounting ofa swinging fork is similar to that described in relation to FIG. 5except that the fork is mounted directly on the casing 85. Thus thecasing is formed with a` pin 108. At the ends of the bore 106 there areprovided faces 109 which are engaged bybearing washers 110 which areinterposed between the faces and pivot bushes 111 received in the limbs112 of the 'fork 105. The bushes are shielded by end plates 112 clampedtog-ether by a pin 113 and sealed by O- rings 114.

The operation of the arrangement described in relation to FIGS. 7 and 10is identical to the operation of the arrangement described in relationto FIGS. 1 to 6 but in FIGS. 7 to 10 there is a unitaryconstructionhaving the casing which is formed with the bores to receivethe mountings 86 and 88 and the pivotal mounting of the swinging fork105.

FIG. 11 shows an alternative form of resilient bush applicable to themountings 86 and 88 and comprising a resilient bush 115-bonded to ametal sleeve 116 but frictionally engaging directly a bore 116 in acasing 117.

FIG. l2 shows an alternative means of providing adjustment of the endfloat. The construction is applicable to the mountings shown in FIGS. 2,3, 8 and 9 but is described in relation to the first resilient mountingshown in FIG. 2. Thus, a mounting 118 is interposed between the lowerfront engine mounting plates 21 andmounting plates 26. The shaft 29 isFIG. 2 is replaced by a bolt 119 which carries, at its head end, anadjusting sleeve 120 which is receivedvin an outer thrust plate 121fixed to one mounting plate 21. The other end ofthe bolt 119 isthreadedly 'received in the other outer thrust plate 122, fixed to theother mounting plate 21, and carries a lock nut 123. The end float maytherefore be adjusted by means of the bolt 119 and sleeve 120,therebeing no need for shims 43. The construction of the rest of themounting is similar to that described in connection with FIG. 2 and willnot be discussed further.

We Claim:

1. A chain driven vehicle comprising a frame, a power unit movablymounted on the frame but having a neutral position relative thereto, afork pivotally mounted on the power unit, a driving wheel rotatablymounted in the fork, a chain drive connecting the driving wheel to thepower unit, and three mountings between the power unit and the frame,the mountings being located respectively at the apices of a trianglelying in a plane perpendicular to the axis of rotation of the drivingwheel, two of the mountings comprising a first rigid mounting elementfixed to the power unit, a second rigid 'mounting element fixed to theframe and a mass of resilient material so located between said elementsthat by movements of the power unit relative to the frame in all. firstdirections radial to said axis the material is loaded in the same onemanner of the two manners shear and compression, and so that by suchmovements in all second directions parallel to said axis the material isloaded in the other of said two manners, the mountings controlling theamplitude of such movement so that the permitted amplitude of themovement from said position in said first directions is a number oftimes greater than the permitted amplitude of the movement from saidposition in said second directions.

2. A vehicle according to claim 1 wherein in at least one of saidmountings said mass is located so that lthe material is loaded incompression during said movements in said first directions, the mountingincluding cooperating abutments on the mounting elements and whichwhichA positively limit relative movement ofthe elements in said seconddirections.

3. A vehicle according to claim 2 in which the first element of said onemounting includes a shaft secured to one of the frame and the powerunit, the second element includes a tubular assembly secured to theother of the frame and the power unit and said mass is in the form ofbush means engaging the shaft and the tubular assembly, the mountingincluding antifriction washers between the cooperating abutments.

4. A vehicle according to claim 3 wherein the bush means is bonded toinner metal sleeve means which engages the shaft and to outer metalsleeve means which engages a mounting sleeve fixed to, or forming partof, the power unit or frame, the outer and mounting sleeves forming thetubular assembly.

5. A vehicle according to claim 3 wherein the resilient bush means isbonded to an inner metal sleevel which engages the shaft, the bush meansengaging directly a mounting sleeve fixed to, or forming part of, thepower unit or frame and forming the tubular assembly.

6. A vehicle according to claim 3 wherein said one mountv ing includesfurther resilient bush means mounted on the shaft and of lessercross-sectional size than the first mentioned bush means so that thereis clearance between said further bush means and the tubular assembly.

7. A vehicle according to claim 1 wherein at least one of said mountingssaid mass comprises one or more resilient

